Eyes in the sky put SES a step ahead of flows

By Ben Cubby ENVIRONMENT EDITOR

December 11, 2010 — 3.00am

RADAR beamed from satellites is being used to track the state's floods for the first time, allowing the most accurate flood predictions yet seen in NSW.

It may be of little immediate consolation to those mopping up their flooded homes today, but the satellite data has allowed the State Emergency Service to plan ahead and evacuate areas long before the waters begin to rise.

The operation is being run by the University of NSW, which is co-operating with German and Italian operators, who have programmed their satellite to scan inland NSW and map the swelling rivers and lakes.

''The problem with taking photographs from aircraft is you can't always see the ground, but radar can see through the clouds,'' said associate professor Linlin Ge, the manager of the program.

He was contacted late last week by the state government and the SES after the technology was successfully used to track fire fronts during the Victorian bushfires last year.

Using radar also avoids the problem of confusing turbid, brown floodwater with land because water reflects radar waves back to the satellite in a uniform way, whereas the earth partially absorbs the waves.

''We just send the request to Italy and Germany and they program their satellites to take photos from their orbits at the right time,'' Dr Ge said.

''Once the image is taken, we have to wait for it to travel to their ground-receiving station, then for it to be rendered as an image.''